The analysis of Bianchi IX models can be very complicated and it is often convenient
to describe the system in terms of the Misner variables [1]}, [2]},
in the context of the so-called Mixmaster Universe;
that is, instead of using the scale factors, the system is characterized in terms of the spatial volume and two anisotropic shape-parameters.
The dynamics of these models is then described as a free particle with a potential that drives the transitions between Kasner regimes
via exponential walls [1]}, [4]}, [5]}, in the so-called “cosmological billiard” [6]}, [7]}.
A simpler scenario corresponds to a Bianchi II universe. This model presents only one transition between two different Kasner epochs
on its evolution towards the singularity. Nonetheless, any Bianchi IX spacetime can be understood as a succession of
Bianchi II models providing transitions among different Kasner epochs [8]}.
